What is the Origin of Muscle Protein Synthesis Rates?

This term is central to exercise physiology and nutritional biochemistry, focusing on the kinetics of myofibrillar turnover. The concept evolved from nitrogen balance studies to modern isotopic tracer techniques for precise measurement. It is the direct metric of muscle anabolism.

What is the Mechanism of Muscle Protein Synthesis Rates?

MPS is primarily regulated through the PI3K/Akt/mTOR signaling cascade, which integrates signals from mechanical loading (exercise) and circulating anabolic hormones. Adequate essential amino acid intake, especially leucine, acts as a necessary permissive factor for mTOR activation. Sustained elevated MPS rates, relative to muscle protein breakdown, are required for net muscle accretion.

Muscle Protein Synthesis Rates

Meaning

Muscle Protein Synthesis Rates (MPS) quantify the speed at which new contractile proteins, primarily actin and myosin, are manufactured within skeletal muscle fibers, a process essential for hypertrophy and repair. These rates are highly sensitive to nutritional amino acid availability and anabolic hormonal milieu, particularly insulin and testosterone signaling. Measuring MPS provides insight into net muscle balance.